Rotary encoder applied in wind turbines！

Wind turbines commonly used in three types of rotary encoder is incremental, absolute and mixed type, in which each of these technologies have their advantages and disadvantages. The following overview will help guide the design engineer to find the best encoder corresponding to various parts of the system.

Incremental encoder
Incremental rotary encoder is a single-turn equipment, in every one rotation axis of a fixed number of pulses are generated. One advantage of this type of feedback is that it is capable of real-time response to changes in shaft speed, making it ideal for tracking turbines revolutions per minute (rpm). In addition, it has a wide range of applications and lower cost than other types of advantages.


Incremental encoder can be used to control blade pitch and yaw angle change, but it can not save location data. Validation and tracking the relative position of the blades and the engine will require an increase in the control system design additional input from proximity switches or Hall effect sensor as a reference point.

Absolute encoders
Absolute rotary encoders with single-turn or multi-turn type, it is light having a plurality of recording on a magnetic disk or some type of reception system by reading to distinguish axial position. This type has the ability to save location data, even if the control system is to be powered down. Multi-turn type include the number of rotations (accurate to one thousand) for recording the shaft gear stage, no longer need to use batteries to store location information. Location data is read directly, rather than incrementally read, and can be used quickly after power.


Absolute encoders provide position feedback data via SSI, Profibus, DeviceNet or CANopen serial interface. These interfaces may limit the data transfer rate feedback position, so it is not real-time. Therefore, the absolute encoder can not be used to track the rate of the generator. However, this does not affect the position of the generator which is used to track changes in a slower, it does not affect the blade pitch control is used in some systems.

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